SWIFT trial results presented at International Stroke Conference

7th February 2012

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An experimental device for removing blood clots in stroke patients dramatically outperformed the standard mechanical treatment, according to research presented on 3 February at a late breaking trial session by Jeffrey L Saver, Stroke Center director, University of California, Los Angeles, (UCLA), USA, at the American Stroke Association’s International Stroke Conference 2012.

Results from the SWIFT (Solitaire with the intention for thrombectomy) study show that the Solitaire FR revascularisation device (ev3 / Covidien) opened blocked vessels without causing symptomatic bleeding in or around the brain in 61% of patients, compared to 24% of cases performed with the FDA-approved Merci retrieval system (Concentric Medical / Stryker). The Solitaire cerebral revascularisation device is not yet approved by the FDA in the USA.

The use of the Solitaire also led to better survival three months after a stroke. There was a 17.2% mortality rate with the new device, compared with a 38.2% rate with the Merci retriever.

“This new device heralds a new era in acute stroke care,” said Saver, the study’s lead author and a professor of neurology at the David Geffen School of Medicine at UCLA. “We are going from our first generation of clot-removing procedures, which were only moderately good in reopening target arteries, to now having a highly effective tool. This really is a game-changing result.”

For the trial, researchers randomly assigned 113 stroke patients at 18 hospitals to receive either Solitaire or Merci therapy within eight hours of stroke onset, between January 2010 and February 2011. The patients’ average age was 67, and 68% were male. The time from the beginning of stroke symptoms to the start of the clot-retriever treatment averaged 5.1 hours. Forty per cent of the patients had not improved with standard clot-busting medication prior to the study, while the remainder had not received it.

At the suggestion of a safety monitoring committee, the trial was ended nearly a year earlier than planned due to significantly better outcomes with the experimental device.

Other findings included:

• Two per cent of Solitaire-treated patients had symptoms of bleeding in the brain, compared with 11% of Merci patients. • At the 90-day follow-up, overall adverse event rates, including bleeding in the brain, were similar for the two devices. • Fifty eight per cent of Solitaire-treated patients had good mental/motor functioning at 90 days, compared with 33% of Merci patients. • The Solitare device also opened more vessels when used as the first treatment approach, necessitating fewer subsequent attempts with other devices or drugs.

“Nearly a decade ago, our UCLA Stroke Center team invented the first stroke retrieval device — the Merci retriever — and now we are pleased to have helped develop and successfully test a superior, next-generation clot removing device,” said Reza Jahan, associate professor of radiology at UCLA and the study’s principal neurointerventional investigator, who also led the pre-clinical studies. “It is exciting to have a highly effective new tool that can improve the outcomes for more stroke patients.”